The invention relates to a gear mechanism for a heald shaft drive.
Weaving machines or looms are equipped with a so-called heald shaft or heald frame, which is an essentially rectangular frame carrying a large number of healds. The healds purposely guide the warp threads out of a warp thread plane in order to form a shed. For this, the heald shaft must be moved up and down according to specific settings with the aid of so-called shaft drives that generate an oscillating back and forth movement at the power take-off. This movement is transmitted via a rod assembly to the heald shaft. The oscillating back and forth movement of the power take-off is normally derived from a constant rotational movement of a drive shaft. If an eccentric gear mechanism is used for this, a fixedly specified connection exists between the rotational movement of the input shaft and the oscillating movement at the power take-off, wherein this movement for the most part corresponds to a sine movement.
Reference DE 691 09 899 T2 discloses different options for superimposing a movement with periodic acceleration and delay onto a constant rotational movement at the input of the shaft gear mechanism. Used for this can be a gear mechanism consisting of a hollow gear, two rotating planet gears and a coupling mechanism. The rotating planet gears are connected via cranks and connecting rods to the lever arms on the output shaft in order to rotate the output shaft.
With this type of gear mechanism, the load strain on the two planet gears can be different.
Starting from the above, it is the object of the present invention to create an improved gear mechanism for driving a heald shaft.